Conventional lighting for various space-illumination applications (e.g., residential, office/workplace, retail, commercial, industrial, recreational, sporting, entertainment and outdoor environments) generally involves light sources coupled to a source of power via manually operated mechanical switches. Some examples of conventional lighting include fluorescent, incandescent, sodium and halogen light sources. Incandescent light sources (e.g., tungsten filament light bulbs) are perhaps most commonly found in residential environments, while fluorescent light sources (e.g., ballast-controlled gas discharge tubes) commonly are used for large lighting installations in office and workplace environments, due to the high efficiency (high intensity per unit power consumed) of such sources. Sodium light sources commonly are used in outdoor environments (e.g., street lighting), and are also recognized for their energy efficiency, whereas halogen light sources may be found in residential and retail environments as more efficient alternatives to incandescent light sources.
Unlike the foregoing lighting examples, light emitting diodes (LEDs) generally are semiconductor-based light sources often employed in low-power instrumentation and appliance applications for indication purposes. LEDs conventionally are available in a variety of colors (e.g., red, green, yellow, blue, white), based on the types of materials used in their fabrication. This color variety of LEDs recently has been exploited to create LED-based light sources having sufficient light output for new space-illumination applications.
For example, as discussed in U.S. Pat. Nos. 6,016,038, 6,150,774, 6,166,496, and 6,292,901, each of which patents is incorporated herein by reference, multiple differently-colored LEDs may be combined in a lighting fixture, wherein the intensity of the LEDs of each different color is independently controlled (e.g., varied) to produce a number of different hues. In one example of such an apparatus, red, green, and blue LEDs are used in combination to produce literally hundreds of different hues from a single lighting fixture. Additionally, the relative intensities of the red, green, and blue LEDs may be computer controlled, thereby providing a programmable multi-color light source.
Furthermore, as discussed in the aforementioned patents, and additionally in co-pending U.S. patent application Ser. No. 09/870,193, filed May 30, 2001, entitled METHODS AND APPARATUS FOR CONTROLLING DEVICES IN A NETWORKED LIGHTING SYSTEM, incorporated by reference herein, individual computer controllable LED-based multi-color light sources may be adapted to be coupled together to form a networked lighting system, wherein each light source is independently addressable. In such a network, one or more illumination programs may be executed to strategically route lighting data to any one or more of the independently addressable LED-based multi-color light sources, so as to generate a wide variety of dynamic lighting effects.